Doubts raised about illegal drug use surveys

A scientific study reported in two related articles in the Journal of Drug Issues raises serious doubts about the nation's illegal drug use surveillance programs. Scientists, policy makers, and the media depend on surveys to identify the extent of drug use nationwide. The study documented how drug use surveys may not accurately reflect changes in drug use, but be more related to how willing a respondent is to disclose the extent and type of drug use.

Researchers at The National Development and Research Institutes, Inc. (NDRI), Andrew Golub, Hilary Liberty, and Bruce Johnson examined reported use of various drugs by arrestees interviewed at 37 locations across the nation as part of the Arrestee Drug Abuse Monitoring (ADAM) Program. This program, financed by the Federal government, both asks arrestees to report on their recent drug use and also tests their use with a urine sample. They found that responses often reflect differences in how willing the respondents were to disclose their use. This "willingness-to-disclose" varies depending on the type of drug questioned, location in the country, and population groups.

Arrestees were much more willing to disclose marijuana use than use of other drugs. Nearly all actual marijuana users in one city, as documented by urine testing, self-reported recent use 93% of the time. In another city, disclosure of marijuana use was 68%. Disclosure of cocaine and crack use was significantly lower, ranging from 28% up to 70%, depending on the location. There were also differences in disclosure associated with age, race, ethnicity, gender, and variation depending on the year of the survey.

These findings raise serious questions about the nation's use of drug survey data. Author Bruce Johnson noted: "Users of such surveys need to continually ask whether reported differences in drug use reflect actual differences in use or differences in willingness-to-disclose use." Based on this study, Golub, Liberty and Johnson conclude that major drug use surveys should be supplemented with drug tests. At least a portion of all survey respondents should be tested in order to estimate respondent's willingness-to-disclose use and its variation across different drugs and different time periods. At the time of the study, the ADAM program was the only major survey that routinely collected biological data.